How aggressively the city of San Diego should fight climate change will be a hot topic in coming months, with Mayor Kevin Faulconer starting to move forward with an ambitious plan that many of his political allies oppose.

The worsening drought and the earlier-than-usual start this year of San Diego’s fire season have increased momentum behind efforts to reduce greenhouse gases.

A coalition of local business and real estate organizations, however, contends the city’s plan would go too far too quickly and could damage the local economy.

Faulconer, a Republican, has said he’ll definitely make some changes to the proposed plan, which was crafted last winter by Democratic City Councilman Todd Gloria while Gloria served as interim mayor.

But Faulconer hasn’t said how significant those changes will be or which elements of the plan he will amend or eliminate before presenting it to the City Council sometime next year.

Backlash against the plan, which has been called one of the most aggressive in the nation, has focused primarily on a regulation that would force property owners to make their homes and commercial buildings more water and energy efficient before they can sell them.

Other elements include incentives and regulations aimed at creating a sharp increase in the use of mass transit and bicycles for commuting, and having San Diego get all of its energy from renewable sources like solar and wind by 2035.

Gloria, who resumed his role as council president when Faulconer became mayor in March, said that part of the reason his plan was so bold was that he anticipated subsequent negotiation.

“I wanted to propose something aggressive knowing that politics is the art of compromise,” Gloria said. “Every bit of the plan is up for amendment or change.”

Gloria said he’d be disappointed if the changes are so significant that San Diego isn’t perceived as a leader on the issue.

“The aggressiveness of the goals is a reflection of the seriousness of the problem,” he said. “San Diego is a special place because of our climate and quality of life, and both of them are threatened.”

Gloria said the mandate that houses and commercial buildings be retrofitted before they can be sold was not among the most important elements of his plan.

“The emission reductions we want to hit would come more from changes in transportation and energy reduction than in the retrofitting of existing structures,” he said.

That’s good news for the San Diego Association of Realtors, which strongly opposes that mandate as something that would prevent many people from selling their homes.

“It creates a huge financial burden and that is of great concern,” said Jordan Marks, the association’s director of governmental affairs.

Senior citizens on fixed incomes would be particularly affected, he said.

He also said the mandate wouldn’t achieve its goal of accelerating remodels and retrofits of buildings because it would discourage people from buying houses with plans to upgrade them and quickly sell.

“We’ll see an onerous financial burden put on sellers who comply, and it won’t achieve the outcome of upgrading our housing stock, which is the end goal,” Marks said. “This is not an efficient method.”

The coalition opposed to Gloria’s plan, which also includes the San Diego Regional Chamber of Commerce and the Building Industry Association, has similar complaints about other elements of the plan.

A joint letter they sent to Gloria in January says the plan should focus more on incentives and less on regulations and penalties.

They also criticized the proposal for considering greenhouse gas emissions levels in 2035, contending 2020 is far enough into the future, and for going beyond state and federal requirements on emissions reductions.

The kind of climate action plan they seek would be similar to one proposed in 2011 by former Mayor Jerry Sanders and then abandoned when former Mayor Bob Filner was elected in 2012.

Supporters of Gloria’s plan say Sanders’ approach, which focused almost entirely on voluntary efforts, would make the city vulnerable to litigation.

In the bigger picture, critics have questioned whether costly local, state and even national plans to address climate change will have the necessary global impact.

Meanwhile, San Diego County and the San Diego Association of Governments have been criticized by Superior Court Judge Timothy Taylor for adopting climate plans that lack regulation, accountability and enforceability.

Kayla Race, a policy analyst for the Environmental Health Coalition in National City, said threats of litigation and the need to act quickly to combat climate change means the city should move forward with Gloria’s plan as soon as possible.

“It’s definitely an ambitious plan and we like that,” she said, adding that Gloria amalgamated pieces of aggressive climate change legislation from all over the country. “It’s really picking from the best and combining all of those.”

Race said if the mandate for building retrofits is removed, the city should look to add other elements to the plan that would achieve the same overall reduction in carbon emissions. But she said Gloria’s plan should go forward without change, suggesting compromises should come when the city is drafting ordinances to specifically carry out the framework of policies envisioned in the plan.

“The plan is ready to go and we’re just waiting on Mayor Faulconer,” she said.

While Faulconer declined requests for an interview, his staff said this week that an update on the plan will be presented to the city’s environment committee on July 23. They didn’t say whether that presentation would include any possible revisions to the plan.

The mayor’s staff also said that each city department recently completed an analysis of how the plan would affect them, and that Faulconer expects to hire a sustainability program manager in mid-July to help implement the plan. The annual salary for that job will be more than $100,000.

In addition, the mayor’s staff said they expect to start accepting comments from the public about the plan this fall. An analysis of the plan’s potential environmental impacts should also start soon, with public comments on that document expected late this year or early next year.

Gloria said he expects the city to end up with a quality climate action plan.

“I think the new mayor has taken his time to put his own imprint on the plan, and ultimately a dialogue between the council and the mayor will produce something that appropriately addresses one of the most significant challenges facing not just our city, but the world,” Gloria said.